Sharpness Throughout

I commonly use focus stacking to extend the area of sharpness within a photograph. This picture of the Beckman Institute of Advanced Science and Technology at the University of Illinois is an example of a simple two frame blend to render the photograph sharp throughout:

Beckman InstituteBeckman Institute for Advanced Science and Technology at 405 N Mathews Avenue on the campus of the University of Illinois at Urbana-Champaign in Urbana, Illinois on February 8, 2018

In an image like this, my goal is the render both the foreground object as well as the far more distant building in sharp focus. The foreground object is very close to my lens...the tripod legs were touching the edge of the disk. To accomplish this, I captured two photographs...one focused on the foreground object and the second on the building. I later blended the two exposures in Photoshop to achieve sharpness from front to back.

Another method is to use a smaller aperture (f/22, for example) to extend the focus area. However, this foreground object was so close that even a narrow aperture wouldn't render everything sharp. Additionally, sharpness tends to fall off as the aperture becomes smaller due to diffraction. Also, unless your sensor is super clean, f/22 will reveal every single dust particle and make removing all of those spots a more tedious post processing exercise. So, I dial in the sweet spot for my lens (usually about f/8) and focus stack multiple frames. That way, I have the best of both worlds--the use of the sharpest aperture for my particular lens and an extremely wide area of sharpness.

Comments

Glenn Nagel Photography

Hi Joaquin,

With a photograph such as this, the exposure was the same for the two shots. If the exposures are different, I use Lightroom to make adjustments to the RAW files to get the two exposures to look comparable to make the blending more seamless. In all cases, I export the RAW files into Photoshop as PSD files. The first step is to blend the two images. From there, I edit the blended image just as if I am working with one image.

Glenn

Joaquín(non-registered)

Hi Glenn,

I have a small question. Do you blend the pictures before or after processing them? I mean, it is possible to blend them into a new RAW file and then edit it, or do you have to edit them with the same parameters and then blend the corresponding JPGs?